1. Field of the Invention
The invention relates to a feeding unit having a forwarding mechanism in which belts are installed around a plurality of pulleys. More specifically, the invention relates to, for instance, a feeding unit for forwarding consumed stencil paper to a predetermined scrapping position in stencil printing machines and the like.
2. Description of Related Art
A rotary stencil printing machine has a cylindrical drum that is driven to rotate about a shaft center thereof. At least a part of the circumferential wall of the cylindrical drum is used as a printing region through which ink can pass. An ink supply means for supplying the ink into the inner surface of the circumferential wall is provided inside the cylindrical drum. A perforated stencil paper for performing the stencil printing is wound around the outer circumfernetial surface of the cylindrical drum. A printing sheet fed as the cylindrical drum rotates is pressed onto the cylindrical drum by pressing means arranged on the outer side of the cylindrical drum. The ink is introduced into the printing sheet through an image formed on the perforated stencil paper wound around the cylindrical drum, so that the stencil printing can be performed on the printing sheet.
The aforementioned stencil printing machine includes: a stencil discharging container that contains a consumed stencil paper; and a feeding unit that forwards the consumed stencil paper to the stencil discharging container. Some feeding units employ a feeding mechanism that includes pulleys and belts.
That is, a plurality of pulleys are pitched at a predetermined interval on each of two parallel running rotary shafts, and belts are installed around the pulleys of one rotary shaft and those of the other rotary shaft, respectively. The thus constructed feeding means are arranged so as to confront each other up and down. By rotating both feeding means in directions opposite to each other, a consumed stencil paper is fed while nipped by the belts of the upper and lower feeding means.
A conventional feeding unit employed in the stencil printing machine can forward a consumed stencil paper without any problem as long as the thickness of the stencil paper is uniform. If the consumed stencil paper is partially folded and has the folds bonded to each other by the ink, then the thickness of the stencil paper may, in some cases, becomes ununiform in a width direction that is orthogonal to a stencil paper forwarding direction. In such cases, the belts of the feeding unit do not come in contact with the thinner portion of the stencil paper adequately, which prevents the stencil paper from being forwarded in the correct condition, causing the stencil paper to jam along the forwarding path.